1. Flexsys America L.P., 260 Springside Drive, P.O. Box 5444, Akron, Ohio 44334-0444, Center of Heterocyclic Compounds, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611-7200, and Department of Chemistry, University of Tartu, Jakobi St. 2, Tartu 51014, Estonia